Vacuum pump



Oct. 22, 1935. w H SCHULZE 2,018,153

VACUUM PUMP Filed Jan. 2l, 1932 2 SheetS-Sheet l Oct. 22, 1935. w H SCHULZE `2,018,153

VACUUM PUMP 2 Sheets-Sheet 2 Filed Jan. 21, 1952 Patented' oet. 22, 1935 UNITED STATES PATENT OFFICE VACUUM PUMP ware Application January 21, 1932, Serial No. 587,857

3 Claims.

This invention relates to improvements in a combined fuel pump and vacuum pump booster adapted for use in association with motor vehicles.

There has been developed a fuel pump for feeding fuel from a supply tank to the carburetor of an engine consisting of a pump casing adapted for mounting on the engine casing to derive actuation from an engine-driven element within the engine casing and including a diaphragm pumping element having a resiliently variable discharge stroke.l It has also been common practice to operate the windshield wiper or other devices of the vehicle by vacuum pressure derived from the intake manifold. It is well known that it is impossible to maintain regularity of operation of the windshield wiper or other devices when the intake manifold vacuumv alone is utilized, since the manifold vacuum varies in accordance with the load and speed of the engine.

According to the present invention, it is proposed to combine a vacuum pump booster with the fuel pump whereby the vacuum pump is operated by the same element which drives the fuel pump and assists in maintaining regular operation of the windshield wiper or other devices by building up 'vacuum pressure when the intake manifold pressure is insuilicient.

It is a purpose of the present invention to mount the vacuum pumpv on the lower side of the casing which serves'as a mounting for the fuel pump and a desirable feature of the present invention consists in positioning the vacuum pump concentric with the fuel pump.

By mounting the vacuum pump concentric with the fuel pump it is possible to slidably associate the respective stems for the pumping diaphragms of the fuel and vacuum pumps and to operate both the stems from a single pick-up member slidably associated with one of the stems.

It is also a feature of the present invention that th'e diaphragm or piston of the vacuum pump has a resiliently variable suction stroke in distinction to the resiliently variable discharge strokes of the diaphragm for the fuel pump and that both pumps are operated by a constant stroke lever carried by the pump casing which is driven from the engine. Thus the pumps will bel actuated in accordance with the demands for fuel or vacuum pressure while the lever continues to move with a constant stroke.

Further and additional objects and advantages of the present improvements will be more readily apparent from' the following description taken (Cl. 23o- 38) in connection with the attached drawings, in

Which- Figure 1 is a diagrammatic installation of a combined fuel pump and vacuum pump for operating a windshield wiper; 5

Figure 2 is a vertical section taken through the combined pumps;

Figure 3 is a detail section of the vacuum Pump;

Figure 4 is a detail section taken on the plane 10 indicated 4-4 in Figure 3;

Figure 5 is a detail section of a modification of the vacuum pump, and y vFigure 6 is a detail section illustrating a. fur.- ther modification of the vacuum pump. 15

In Figure 1 there isshown pumping mechanism included in a casing, generally indicated I0, operated by a lever I2 carried by pivot I4. The casing has a flange I6 for mounting on an engine casing and the lever I2 is adapted to extend 20 into the engine casing for thrust engagement with an engine-driven cam I8'. The casing I0 includes a fuel pump 28 and a vacuum pump 22. 'I'he fuel pumpA has an inlet connection 24 to the fuel receiving chamber 26 from a source of fuel 25 supply and an outlet connection 28 from the vapor dome pressure chamber 30 of the fuel pump and leadingto the' carburetor of the engine. A windshield Wiper arm 32 is operated by oscillating shaft 34. The wiper casing 36 has mecha- 30 nism for operating the shaft 34 in the desired manner through the vacuum pressure derived through pipe 38 which leads to the inlet connection 40 of the vacuum pump 22. The outlet connection 42 of the vacuum pump is connected 35 by a pipe 44 to the intake manifold 46 of the engine.

The internal construction of the casing I0 is more clearly disclosed in Figures 2 and 3 in which there is a fuel pumping chamber 48, v*which is 40 expanded and reduced by the movement of a reciprocable pumping diaphragm 50. A spring pressed inlet valve 52 controls the entrance of fuel into the pumping chamber and prevents back ow and a, spring-pressed outlet check valve 54 controls the delivery of fuel to the outlet pipe line 28. The pumping diaphragm is urged for its discharge stroke by a compression spring 56 in the usual manner. A reciprocable stem 58 connected to the diaphragm 50 is guided by 50 the boss 6D of the casing I 0 and is moved in a downward direction for a suction stroke of the pumping diaphragm 50 through means of a collar 62 slidable on the reduced lower end 64 oi' the stem 58 and engaged by the yoke-shaped end 55 Il of the lever I2. 'Ihe lever I2 is maintained inv thrust engagement with the engine-driven cam Il by means of a follower spring Il. The spool 02 has clamped to its lower end a cushion abutment 10 which is adapted to engage ashoulderedabutment 12 on the lower end of the reduced portion u of the stem Il. Thus, if the force of the spring is insumcient to move the pumping diaphragm for its discharge stroke, lost motion will occur between the spool 62 and the shouldered abutment 12.

The casing I0 has a bearing 1l for acupshaped stem 16 which is secured to the center of the lreciprocable vacuum pump diaphragm 18. The abutment 12- on the lower end of the pump stem 5I is slidable in the stem 1B, as shown in Figure 3 and is provided with grooves 1l fol'- lubricating the bearing. The cup-shaped stem 1l has a slotted opening I0 cooperating with the opening 82 in the ilxed guide bearing portion 14 to permit ilow of lubricant from the cavity of the casing I0 into the bearings for the slidable stems. l

An expansible and reducible vacuum pump chamber Il, of which the diaphragm 1| forms a movable wall, has an inlet check valve I6 held in normal seated position by a spring 8l retained in place by the threaded plug 90 and an outlet check valve 92 held in normal seated position by spring N', retained by the threaded outlet connection I2. The removable head 06 of the vacuum pump, which contains the inlet and outlet check valves has a guide bearing 98 for a sleeve III. secured to the reciprocable stem `'Il of the pumping diaphragm. A spring |02, reacting between the head 06 and the stem 1I, serves to move the diaphragm 1I in a suction direction, the diaphragm 1l being moved in a discharge direction by the operation offlever l2.

As shown in Figure 5 the guiding sleeve Ill may not be used. Instead, a spring I may be employed reacting between the cup-shaped portion I" of the head Il and the diaphragm. The

space within the cup-shaped portion which receives the spring I is materially reduced by an enlarged head I forming a nut member for securing the stem Il to the diaphragm 1I.

AIn Figure 6 another modification is disclosed in which a spring III, for producing the suction stroke of the diaphragm 1I, is arranged surrounding the guide bearing 14 of the casing and reacts upon a nange H2 integral with the stem 16. In this form the capacity oi' the pumping chamber Il may be materially reduced.

By combining a fuel pump and vacuum pump in this manner it is possible to operate both pumps by a common engine-driven lever. Both pumps may be operated with a variable stroke, that is, the fuel pump will not deliver fuel above a discharge pressure determined by the force of the spring It and, in a similar manner, the vacuum pump will not operate for suction unless the spring, which reacts upon the diaphragm 1I is strong enough to move the diaphragm in a suction direction against the vacuum condition existing in the intake manifold of the engine and conduit. Therefore. as long as svtiicient suction "is being created from the intake manifold, the

diaphragm 10 will be maintained inoperative and the airwillbeexhausted throughthepipeline. 2l into the pumping chamber I4 and into the intake manifold. If the depression in the intake s manifold becomes insufllcient, the spring acting upon the diaphragm 1l will then expand and move the diaphragm Il for a suction stroke and movement of the lever I2 will then pick up the stem 18 and move the diaphragm 1l in a dis- 10 charge direction.

I claim-2 l. In a pumping device, a casing having an expansible and reducible pumping chamber, a pumping member forming a movable wall of said 15 pumping chamber, a stem secured to said-pumping member, a spring reacting between said casing and said stem to move said pumping member in a direction to expand said pumping chamber, said stem having a socketed opening formed 20 therein, a second stem member slldably iltted in the socketed opening of said first stem member,

a pick-up member supported by said second stem, said first-mentioned stem having an abutment face adapted for engagement by said pick-up 25 member when said pick-up member is moved in one direction and a pivoted operating lever carried by said pump casing for imparting a constant stroke of movement to said pick-up member whereby said pumping member is moved for reduction of said pumping chamber through actuation of said pick-up member.

2. In a pumping device of the class described, a casing having a pumping chamber therein, a reciproeable pumping memberl cooperating with said pumping chamber, resilient means for moving said pumping member in a direction to enlarge said pumping chamber, said resilient means positioned with its axis coincident with the axis of movement of the central portion of the pumpin member, a stem disposed in said casing concentric with the axis of said pumping member, a spool-shaped pick-up member supported by said stem and adapted to transmit movement to said pumping member against the resistance of said resilient means by thrust engagement therewith and a cam-actuated lever pivotally supported by said casing having a yoke-shaped end in operative engagement with said spool-shaped member. Y

3. In a pumping device of the class described, a casing having a pumping chamber therein, a reciproeable member cooperating with said pumping chamber, resilient means for moving said pumping member in a direction to enlarge 55 said pumping chamber, a stem fixed to said pumping member, a spool-shaped pick-up member supported for reciprocable movement with respect to said casing, a cushion abutment carried by said pick-up member and adapted to contact said stem and a cam actuated lever pivotally supported by said casing having a yokeshaped end in operative engagement' with said pick-up member to transmit positive movement to said pumping member.

W. H, SCHULZE. 

